Solar prominences
Sketches and Details by Cyprien Pouzenc
Some prominences drawn at the 9 mm Nagler eyepiece, mounted on the
coronograph 107/1200 of the Sirene Observatory (www.obs-sirene.com) at
around 12pm on May 18, 2007 (! Yes, I was somewhat forgotten this
picture :o)
Arch: drawn from 12:13 to 12:20 local time.
Shrubs: drawn from 11:57 to 12:06 local time.
—
Cyp
La Roque d’Anthéron (Bouches du Rhône, France)
+43° 43′ 03″ Nord, 5° 18′ 05″ Est, 175 m
H-Alpha Sun
Sketch and Details by Les Cowley
Comparison Photos by Pete Lawrence
The Sun is an ever-changing target. In H-alpha light, prominences light and
dim, shift and change literally by the minute. Fascinating to watch and
sketch but just how accurate are drawings grabbed in a few minutes during
variable seeing and under a black hood?
May 7th was an opportunity to find out when Cloudy Nights held an
“International Day of the Sun”. Expert UK photographers Peter Lawrence and
Nick Howes suggested imaging or sketching a prominence every 30 minutes on
the hour and half hour!
The day dawned clear and after breakfast the selected prominence was viewed.
It was the ugliest assortment of filaments, clouds and loops that you could
imagine with parts changing and dancing about even as you watched. The
‘scope was a Coronado Solarmax60 mounted on a manual altazimuth. Seeing
started fairly good so I used an 8mm Radian, I need eyeglasses to sketch and
the Radian gives enough eye relief. The drawings were on A4 black Canford
paper filling half the sheet per sketch with Derwent Watercolour pencils
used sharp and dry.
Serious observing started about 8 minutes before each time mark with the
main proportions starting to be put in 5 minutes before the mark. Then finer
and finer details were quickly added, not in any order just wherever good
seeing happened to show them. This quickly brought the time to the mark and
then the whole view was assessed for accuracy. It was changing so fast!
Finally 3-5 minutes after the mark were spent getting the relative
intensities right and generally tidying up.
By 09:45 there were frequent periods of superlative seeing and I changed to
a 5mm Radian and clutched the dark hood around close to shield the daylight.
For long periods (but never, ever during the allocated 10 minute slots!) the
visible structures were exquisitely resolved into delicate stacked filaments
with even those sometimes doubling and breaking into knots – you would need
an hour or hours to capture all that! After 10:30 the seeing deteriorated
and that combined with not a little fatigue ended the sketching run.
Pete Lawrence was imaging some 150 miles to the south with about the same
seeing conditions. He used a Solarscope SF-70, a Rolls-Royce of H-alpha
filters. His images for the same times are on a reduced scale at the base
but you need to see the originals (http://www.digitalsky.org.uk/ and Cloudy
Nights) to really appreciate their superlative quality.
So can sketching such ephemeral objects ever be accurate? I’m still
deciding. There is maybe a tremendous amount to be leaned from a careful
comparison of sketch fragments with simultaneous photographs about how the
eye-brain interprets fine details and tends to join others into spurious
larger structures. If some of that can be understood then hopefully it might
improve the sketching accuracy.
Les Cowley, England
H-Alpha Sun
Sketch and Details by Erika Rix
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 54.0°F / 12.2 °C
Winds: 5.8 mph NW, clear turning to partly cloudy
Humidity: 53%
Seeing: very poor 2/6
Transparency: 4/6
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell, ETX70AT, 8mm TV Plossl
Sketch Media:
H-alpha – Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
White light pores created in Photoshop.
New active region in the ESE quadrant was visible with two crescent shaped plage facing each other during the h-alpha observing session. In white light, seeing was very poor making it invisible at first glance. Eventually my eyes were able to see two dark specks in the AR, appearing to be only umbrae, with the more easterly one slightly darker and thicker.
No faculae were noted in white light.
Of the prominence activity in h-alpha, the long line of southern prominences had filament reaching out over the disk on the far western edge. The large eastern edged prom in this line was leaning at a crook to the east (right) in my FOV. It was also the faintest of the four more prominent prominences around the Sun’s limb.
Solar H-Alpha
Sketch and Commentary by Erika Rix
2008 04 06, 1240ST – 1330ST (1640UT – 1730UT)
Solar H-alpha
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 62.1 °F / 16.7 °C
Winds: 3.5 mph from the East
Humidity: 52%
Seeing: 5/6 with moments of 2/6
Transparency: 4/6
Alt: 51.3 Az: 143.3
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell
Sketch Media:
H-alpha – Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
Added –25 brightness, +15 contrast after scanning in color at 300 dpi. Tilting Sun program used for digital Sun insert.
Sun – Featuring NOAA 10987, 10988, 10989
Sketches and Commentary by Erika Rix
2008 March 26, 1335ST – 1452ST (1735UT – 1852UT)
Solar H-alpha and White Light
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 57.0 °F / 13.9 °C
Winds: West 18 mph gusting to 25 mph
Humidity: 33%
Seeing: 5/6
Transparency: 2/6
Alt: 50.4 Az: 157.5
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell
ETX70 AT, tilt plate, 8mm Televue Plossl
Sketch Media:
H-alpha – Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
Added –5 brightness, +30 contrast after scanning in color at 300 dpi. Tilting Sun program used for digital Sun insert.
White Light – white copy paper, #2 pencil, .5mm mechanical pencil, photographed sketch instead of scanning for better contrast.
It was said that today NOAA 10989 produced an M2-class eruption causing a CME. I have to say that each of the three active regions had very bright plage seeming to curve around the dark specks of sunspots within each region. It’s not often I get such a great view of the sunspots themselves in h-alpha, but today 10988 had the largest umbral area and they all had one or two smaller dark spots. I could hardly wait to pull out the ETX70 with a white light filter to see the sunspots themselves in much greater detail.
Prom activity was very modest. After 3-4 strolls around the limb tweaking the Etalon, 6 areas of very small prominences came to view. The filaments on the disk were showy, especially the large blotchy one to the south of 10988.
With the white light filter, facula was clearly viewable around 10989, reaching out in several directions. Penumbrae were seen in most of the sunspots. I had hoped to increase magnification for a closer view, but with transparency becoming worse, as well as viewing in white light in the front yard rather then in the protection of the observatory, the white light view was already too soft. Increasing magnification would have made it impossible.
Sun in H-Alpha
By Erika Rix
2008 March 23, 1437ST – 1530ST (1837UT – 1930UT)
Solar H-alpha
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 39.0 °F / 3.9 °C
Winds: variable at 3.5mph, light cirrus and then scattered toward the end of session
Humidity: 46%
Seeing: 5/6
Transparency: 4/6 decreasing to 1/6
Alt: 51.2 Az: 187.0
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell,
The new active region on the eastern limb was the first thing I noticed with the 40mm eyepiece. Dropping down to 7mm and adjusting the Etalon made this area rich with details. The seeing today was wonderful allowing higher magnification. A thick clumpy filament reached all the way to the limb, almost coming to a point before reaching out into the darkness of space for a very bright, flattened prominence reaching northward. The view was so three dimensional in appearance that it almost felt like you could reach in with your finger through the eyepiece and hook underneath the filament to pull it towards you. There were many tiny spicules on this eastern limb.
About 30 degrees inward from the East were two bright plage, separated only by a thin darkened line. I didn’t notice a sunspot within it in h-alpha and didn’t take the time to pull out my white light filter rig for a better look. The eye-catching view was when I increased the contrast to show a network of what I believe to be fibrils extending out from a thin filament that was running East to West. The fibrils seemed to extend almost north to south and the whole area looked like an incision with sutures. This area was just south, almost touching the plage and I wouldn’t have noticed it at all had I not tweaked the Etalon for more details to be pulled out.
Going towards the eastern limb, there was a longer area of plage that almost resembled the lunar crater Schiller, one giant footprint on the solar surface.
Although the eastern hemisphere was full of proms, mainly small vivid ones with a few brighter, large ones, there was a gem at the NE limb that was barely visible. I actually skipped over it completely the first time scrolling around the limb. When I moved the FOV, however, I detected a very large faint blotch hovering over the limb. After adjusting the Etalon, zooming in and out, I finally was able to make out this very fibrous prominence. It appeared to only be connected to the limb with one very narrow stalk, and at the beginning of the session, jutted dramatically to the North. Later, when I did a close up sketch of this prom, it actually spread out to the either side with almost a flat top. Truth be told, it reminded me of a clown’s hairdo.
When my session ended, I stood up against the drop down southern wall of the observatory to finish my cup of tea, admiring the countryside and the warmth on my back. Signs of spring are finally here, I thought to myself afterwards as I walked back up the stone steps to the house in my green and yellow flowered rubber gardening shoes, carrying my empty cup and sketchpad.
The Sun in h-alpha, February 16, 2008
By Erika Rix
2008 02 16
Sun in h-alpha
PCW Memorial Observatory, 40.01/-81.56
Erika Rix
There were several prominences scattered about the limb, visible at different
magnifications. I’ve concentrated at the NNE one, which also had a very small reach
in front of the disk when I tweaked the Etalon.
I should have sketched this area larger, or sharpened my pencils better. There was
so much detail within it that my white pencils were too blunt to render them
properly.
With the hunters and their dogs in the fields and woods in front of our observatory,
I wasn’t keen on hanging out too long for more sketches. Thankfully I could close
the door to keep Riser in the observatory with me. As it was, he was antsy, moving
around a lot and making noises…very distracting.
Sketches rendered on black Strathmore Artagain paper, white Conte’ pencil and
crayon, white Prang pencil.
Solar H-alpha sketch collage 2008 02 11, 1214ST -1304ST (1714UT – 1804UT)
By Erika Rix
2008 02 11, 1214ST -1304ST (1714UT – 1804UT)
Solar H-alpha
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 14.0 °F / -10.0 °C
Winds: WNW at 8.1 mph, light scattered and later completely overcast
Humidity: 49%
Seeing: 2/6-5/6
Transparency: 2/6
Alt: 35.9 Az: 176.9
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell,
Sketch Media:
Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
Added -25 brightness, +5 contrast after scanning in color at 300 dpi. I then turned
the image into monochrome. I scanned initially in color to eliminate cross hashes
that the scanner creates in grayscale. Tilting Sun program used for digital Sun
insert.
At first glance in h-alpha around 10x magnification, only two prominences, SSE and
West, popped out at me. I didn’t waste much time with the 40mm eyepiece since I
usually use it for initially getting the Sun in the FOV. At 19x the eastern
prominence looked like two fingers curling towards each other with the southern most
of the two a little brighter. Taking the magnifications to 57x I could make out a
very faint thin line connecting the two and also noted the strands of contrasted
prominence within the two fingers at 33x. Seeing was much worse at the higher
magnifications but I had moments where it settled for a detailed view.
Moving South at low magnification, the prominence appeared to be two separate
entities with the westerly portion of it looking like a hook or letter C opening up
to the East. Increasing magnification with the zoom eyepiece, I was amazed to see
with slight averted vision at first several connections between the two. After
discovering them, I could actually look at them straight on to make out the delicate
network of strands. It was truly beautiful and very delicate.
A similar thing happened to me with the western set of prominences. The most
northerly of the four on the western limb grew almost twice in size with a
magnification of around 33x. The prom itself didn’t grow, but rather my ability to
see the actual size of it with a modest magnification. The additional length of it
disappeared at 57x.
The little set of prominences at the NNE limb became brighter as the session went
and also became better defined with the lower one (more northerly) turning from a
fuzzy little thumbprint into a thin branch reaching to the one that was more to the
East.
I noticed a dark round dot around 40 degrees on the disk from the East and pretty
much on the equatorial line. It was very small and tweaking the Etalon did not show
any signs of plage. Other than that, there were no significant surface details such
as plage or filaments to me visually. The disk was alive with hairlike structures
and a mottled appearance, very pretty.
Solar sketch on January 20th, 2008
By Erika Rix
2008 01 21, 1155ST -1241ST (1655UT – 1741UT)
Solar H-alpha
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 19.0 °F / -7.2 °C
Winds: from the South at 6.9 mph, light cirrus
Wind chill ~ 12F
Humidity: 42%
Seeing: 5/6 with moments of 4/5
Transparency: 2/6
Alt: 29.3 Az: 168.6
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell
Sketch Media:
Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
Added -27 brightness, +6 contrast after scanning.
Tilting Sun program used for digital Sun insert.
Yesterday I had forgotten to record drift before I brought the Maxscope back inside
and closed up the observatory. Not feeling like setting back up again to record
drift, I guessed the orientation incorrectly. Today, I observed close to the same
time as yesterday and with the diagonal near the same position and by comparing
today’s sketch with yesterday’s, I think I can safely say the SW prom that I
sketched was actually a SE prominence. I’m sorry for my error, but happy to supply
a compared view of the two solar sketches.
Solar sketch on January 21th, 2008
By Erika Rix
Please note the differences in the 55 deg PA and the 135 deg PA (approximately)
prominences between the two days. The NE prom developed into a beautiful display
today that at first glance appeared to be a soft mushroom head with hardly a stem
beneath it. Nine minutes later and bumping up the magnification, it took a
completely different structure with clearly several legs reaching to the limb as
well as a pointed tip swaying to the north.
The SE prominence today at first glance was shaped like a beautiful mosque. Bumping
up the magnification made it more difficult to see as much detail because the sky
conditions took a turn for the worst and I had to keep waiting patiently for moments
of clarity to complete the prominence sketch. By the time it became steady and
clear, the prom had changed too much for me to add the fainter portions of it.
The plage that I noted yesterday was no where to be found today.
Solar prominences, January 23rd, 2008 1125ST -1240ST (1625UT – 1740UT)
By Erika Rix
2008 01 23, 1125ST -1240ST (1625UT – 1740UT)
Solar H-alpha
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 21.0 °F / -6.1 °C
Winds: variable at 5.8 mph
Humidity: 63%
Seeing: 6/6
Transparency: 3/6
Alt: 28.1 Az: 160.5
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell
Sketch Media:
Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
Added -30 brightness, +9 contrast after scanning. Tilting Sun program used for
digital Sun insert.
The NE and the SE limbs continue to put on a display for us. I didn’t get a chance
to observe yesterday for all the overcast and light snowfall, but over the past
several days’ observations, it’s been very interesting to watch the changes and
compare observations.
The solar disk had long u-shaped very thin filament looking lines reaching almost
from the SE limb to the inward 1/4th of the disk. The opening of “u” was facing
outward toward the large prominence on that area of the limb. This was the
prominence that I concentrated on today for a sequence that spanned only about 45
minutes’ time. Funny, it seemed much longer than that, and as much as it changed in
that time frame, I would have expected it to have been longer as well. Seeing was
terrific, but transparency was only average with moments of excellent clarity as
well as an orange haze all around the disk in my FOV.
Differences in the first two sketches almost alarmed me and I worried that I had
made one too compact width wise and the other too spread out. There’s a chance that
I may have indeed done that, although as a sketcher, I try to make my sketches as
true to my observations as I possibly can. Once I recorded the last two, though, I
could see the movement of the prominence indeed spreading out, getting fainter to
the eastern side of it with each sketch. It was almost as if that side of the
prominence was getting weaker and losing structure. I would have loved to stay out
all day to record this.
The NE prominence was not quite as tall as the SE prominence, but it was easier to
view, although I did have to adjust the outside etalon as there was quite a
difference between the two prominences for best bandwidth viewing. I normally tweak
as many things as I can with the scope to tease out details in my observations, but
I normally don’t have to adjust the etalon that much between different prominences.
I observed 8 different areas of prominences around the limb total.
